• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.287-288
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• 2015

최근 투명 산화물 전극 (TCO)은 LED, electronic display, solar cell, touch screen panel (TSP) 등 다양한 분야에 많이 사용되고 있다. TCO는 높은 광 투과도와 전도성으로 인해 여러 분야에 많이 사용되고 있으며, 특히 ITO (Sn-doped indium oxide)가 display 분야에 많이 적용되고 있다. 하지만, ITO는 투과도와 면저항의 반비례 관계를 가지므로 더 낮은 면저항이 요구되는 대면적 TSP 분야에 적용되기에는 많은 개선이 필요하다. 따라서, 본 연구에서는 metal mesh film의 연구를 통해 TSP 분야에 사용되는 ITO를 대체하고자 한다. 제작된 mesh film은 모두 면저항은 $15{\Omega}/{\square}$ 이하, 광 투과도 90% (@550nm) 이상을 나타내었다.

• 한국전기전자재료학회논문지
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• 제30권5호
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• pp.288-293
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• 2017

$Fe_2O_3$ is one of the most important metal oxides for gas sensing applications because of its low cost and high stability. It is well-known that the shape, size, and phase of $Fe_2O_3$ have a significant influence on its sensing properties. Many reports are available in the literature on the use of $Fe_2O_3$-based sensors for detecting gases, such as $NO_2$, $NH_3$, $H_2S$, $H_2$, and CO. In this paper, we investigated the gas-sensing performance of a Pt-doped ${\varepsilon}$-phase $Fe_2O_3$ gas sensor. Pt-doped $Fe_2O_3$ nanoparticles were synthesized by a Sol-Gel method. Platinum, known as a catalytic material, was used for improving gas-sensing performance in this research. The gas-response measurement at $300^{\circ}C$ showed that $Fe_2O_3$ gas sensors doped with 3%Pt are selective for $NO_2$ gas and exhibita maximum response of 21.23%. The gas-sensing properties proved that $Fe_2O_3$ could be used as a gas sensor for nitrogen dioxide.

• 마이크로전자및패키징학회지
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• 제29권2호
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• pp.53-58
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• 2022

One of the most promising emerging technologies for the next generation of nonvolatile memory devices based on resistive switching (RS) is the resistive random-access memory mechanism. To date, RS effects have been found in many transition metal oxides. However, no clear evidence has been reported that ZnO-based resistive transition mechanisms could be associated with strong correlation effects. Here, we investigated N, F-co-doped ZnO (NFZO), which shows bipolar RS. Conducting micro spectroscopic studies on exposed surfaces helps tracking the behavioral change in systematic electronic structural changes during low and high resistance condition of the material. The significant difference in electronic conductivity was observed to attribute to the field-induced oxygen vacancy that causes the metal-insulator Mott transition on the surface. In this study, we showed the strong correlation effects that can be explored and incorporated in the field of multifunctional oxide electrons devices.

• The Korean Journal of Ceramics
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• 제6권1호
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• pp.58-63
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• 2000

The preparation of Y-doped $SrZrO_3$powder by ultrasonic spray pyrolysis was investigated as a representative system, in order to produce fine, single phase multicomponent oxide powders. A precursor solution containing metal nitrates, citric acid and ethylene glycol was atomized glycol was atomized with an ultrasonic spray nozzle. Gel particles formed by organic functional groups were pyrolyzed and subsequently calcined at $800^{\circ}C$ to obtain well-crystallized, single perovskite phase. Most of large particles exhibited macroscopic pores and weak agglomeration between primary particles. However, strong agglomeration was observed in the surfaces of large particles. The effect of the microstructures of these particles on size reduction to submicron particles was described.

• 한국재료학회지
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• 제30권5호
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• pp.239-245
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• 2020

Synthesizing one-dimensional nanostructures of oxide semiconductors is a promising approach to fabricate highefficiency photoelectrodes for hydrogen production from photoelectrochemical (PEC) water splitting. In this work, vertically aligned zinc oxide (ZnO) nanorod arrays are successfully synthesized on fluorine-doped-tin-oxide (FTO) coated glass substrate via seed-mediated hydrothermal synthesis method with the use of a ZnO nanoparticle seed layer, which is formed by thermally oxidizing a sputtered Zn metal thin film. The structural, optical and PEC properties of the ZnO nanorod arrays synthesized at varying levels of Zn sputtering power are examined to reveal that the optimum ZnO nanorod array can be obtained at a sputtering power of 20 W. The photocurrent density and the optimal photocurrent conversion efficiency obtained for the optimum ZnO nanorod array photoanode are 0.13 mA/㎠ and 0.49 %, respectively, at a potential of 0.85 V vs. RHE. These results provide a promising avenue to fabricating earth-abundant ZnO-based photoanodes for PEC water oxidation using facile hydrothermal synthesis.

• 한국결정성장학회지
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• 제9권1호
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• pp.29-33
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• 1999

Verneuil 법에 의해 성장된 무색 sapphire {0001}, ${10\bar{1}0}$ 결정면에 전이금속 Cr을 확산시키고, 물리적, 전기적, 광학적 특성을 개선하였다. 확산분말은 금속산화물 분말과 금속분말을 혼합한 후 사용하였다. 혼합분말을 사용하였을 때 확산은 오랜시간 높은 온도를 필요로 하며 상대적으로 서서히 이루어 졌다. 금속분말은 $1{\times}10^{-4}$ torr, $2050^{\circ}C$의 조건에서 1차 기화하였고 이후 $2050~2150^{\circ}C$, 질소가압 6 atm의 확산조건에서 유지하였다. 사파이어의 표면밀도는 0.2254(c)와 $0.1199\;atom/{\AA}^2(a)$이었다. 확산이 이루어진 sapphires는 붉은색으로 변하였다. 고용반응은 ${10\bar{1}0}$ 결정면이 {0001} 보다 더욱 깊게 확산되었고, 면밀도가 확산효과를 결정하는 주요인자이었다.

• 한국전기전자재료학회논문지
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• 제19권1호
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• pp.1-6
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• 2006

High performance $Si_{0.8}Ge_{0.2}$ heterostructure metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated using well-controlled delta-doping of boron and $Si_{0.8}Ge_{0.2}$/Si heterostructure epitaxal layers grown by reduced pressure chemical vapor deposition. In this paper, we report 1/f noise characteristics of the SiGe pMOSFETs measured under various bias conditions of the gate and drain voltages changing in linear operation regions. From the noise spectral density, we found that the gate and drain voltage dependence of the noise represented same features, as usually scaled with $f^{-1}$ However, 1/f noise was found to be much lower in the device with boron delta-doped layer, by a factor of $10^{-1}_10^{-2}$ in comparison with the device fabricated without delta-doped layer. 1/f noise property of delta-doped device looks important because the device may replace bipolar transistors most commonly embedded in high-frequency oscillator circuits.

• Current Photovoltaic Research
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• 제8권2호
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• pp.60-65
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• 2020

In perovskite solar cells with planar heterojunction configuration, selection of proper charge-transporting layers is very important to achieve stable and efficient device. Here, we developed solution processible Cu doped NiO_x (Cu:NiO_x) thin film as a hole-transporting layer (HTL) in p-i-n structured methylammonium lead trihalide (MAPbI₃) perovskite solar cell. The transmittance and thickness of NiO_x HTL is optimized by control the spin-coating rate and Cu is additionally doped to improve the surface morphology of undoped NiO_x thin film and hole-extraction properties. Consequently, a perovskite solar cell containing Cu:NiO_x HTL with optimal doping ratio of Cu exhibits a power conversion efficiency of 14.6%.

• 한국광학회지
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• 제18권3호
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• pp.221-225
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• 2007

근적외선에서 발광하는 새로운 증폭 매질인 Bi 첨가 알루미노실리케이트 유리의 용융 온도를 낮추면서도 증폭 특성이 향상될 수 있도록 금속 산화물을 첨가한 샘플을 제작하여 분광학적 특성을 분석하였다. $Li_{2}O$의 조성비가 증가하면 형광스펙트럼의 반폭치는 증가하지만 형광 강도가 저하되고, $GeO_{2}$의 영향으로는 반폭치와 형광 강도가 동시에 증가하였다. $GeO_{2}$를 첨가한 시료에서 광 증폭 특성을 측정한 결과, 이전의 벌크 샘플에서 얻었던 것보다 우수한 증폭 특성을 가지고 있음을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.5-6
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• 2005

High performance SiGe heterostructure metal-oxide-semiconductor field effect transistors(MOSFETs) were fabricated using well-controlled delta-doping of boron and SiGe/Si heterostructure epitaxal layers grown by reduced pressure chemical vapor deposition. In this paper, we report 1/f noise characteristics of the SiGe MOSFETs measured under various bias conditions of the gate and drain voltages changing in linear operation regions. From the noise spectral density, we found that the gate and drain voltage dependence of the noise represented same features, as usually scaled with $f^1$. However, 1/f noise was found to be much lower in the device with boron delta-doped layer, by a factor of $10^{-1}\sim10^{-2}$ in comparion with the device fabricated without delta-doped layer. 1/f noise property of delta-doped device looks important because the device may replace bipolar transistors most commonly embedded in high-frequency oscillator circuits.